Median Nerve

Last updated 03.11.12

 

Index

 

-  Innervation

-  Pathway

-  Examination

 

Definition

-  Major nerve of upper limb

 

Features

-  Mixed motor & sensory

-  Spinal roots: C5 – T1

-  Branch of brachial plexus

-  Mainly acts below the elbow (innervation)

 

Clinical Relevance of Ulnar Nerve

-  Upper limb neuro exam

-  May become entrapped causing clinical syndromes

-  Carpal Tunnel Syndrome

-  Compression between within carpal tunnel

-  Anterior Interosseos Syndrome

-  Pure motor paralysis of

-   FPL

-   FDP

-   Pronator quadratus

-  Pronator Syndrome

-  Compression between supracondylar ridge & ligament of struthers or as it passes deep to fibrous arch of FDS

 

 

 

Median Nerve Innervation

<Median Nerve>

 

Muscles Innervated

-  Most of anterior (flexor) compartment of forearm

-  Pronator teres

-  FCR

-  Palmaris longus

-  FDS

-  Ulnar half FDP

-  Most of thenar muscles

-  FPB

-  APB

-  Opponens pollicis

-  1st & 2nd lumbricals 

 

Cutaneous Innervation

-  1st, 2nd, 3rd & lateral half of 4th digits

-  Lateral palm

 

Joint Innervation

-  Elbow

-  Wrist

 

 

 

 

Median Nerve Examination

<Median Nerve>

 

 

 

 

 

Median Nerve Pathway

<Median Nerve>

 

-  Axilla

-  Arm

-  Elbow

-  Forearm

-  Hand

 

 

Axilla

-  Formed from lateral & medial cords of brachial plexus

-  Lateral root is lateral cord of brachial plexus

-  Medial root is medial cord of brachial plexus

-  Forms the middle portion of the M of brachial plexus

-  Passes deep to coracobrachialis muscle anterior to axillary artery

 

Arm

-  Passes lateral to brachial artery until midarm where it crosses to the medial side of brachial artery

-  Has no branches in the arm

 

Elbow

-  Medial to the brachial artery & biceps brachii tendon

-  Deep to bicepital aponeurosis & median cubital vein

-  Articular branches of the median nerve

-  Pass to the elbow joint from the median nerve as it crosses the joint

-  Supplies elbow joint

 

Forearm

-  Enters forearm with brachial artery superficial to brachialis

-  Between ulnar & humeral heads of pronator teres

-  Motor branches of median nerve

-  Arises at the proximal portion of pronator teres

-  Supplies

-   Pronator teres

-   Pronator quadratus

-   FCR

-   Lateral half of FDP

-   FDS

-   FPL

-   Palmaris longus

-  Anterior Interosseos Nerve

-  Arises lateral & deep at level of ulnar head of pronator teres muscle within the cubital fossa

-  Passes distally ontop of interosseous membrane with anterior interosseous branch of ulnar artery

-  Between FDP & FPL muscle to supply pronator quadratus muscle

-  Terminates by supplying articular branches to the wrist joint

-  Palmar Cutaneous Branch of the median nerve

-  Arises proximal to flexor retinaculum approx 5cm prox to wrist crease

-  Not effected by carpal tunnel syndrome but may be transacted during carpal tunnel release

-  Becomes cutaneous between tendons of palmaris longus & FCR

-  Passes superficial to flexor retinaculum

-  Supplies cutaneous innervation to skin of lateral palm/thenar eminence

-  Then passes through FDS fibrous arch & attaches to deep surface as it continues distally

-  Lies between FDS & FDP

-  Leaves the deep surface of FDS between the tendons of palmaris longus & FCR in last sixth of forearm into wrist

 

Hand

-  Passes through carpal tunnel at its lateral aspect superficial to tendon of FPL

-  Motor branch

-   Usually branches distal to carpal tunnel

-   May branch off within carpal tunnel

-   +/- pass directly through transverse carpal ligament

-   Supplies

-   Thenar muscles

-  FPB

-  APB

-  Opponens pollicis

-   1st & 2nd lumbricals

-  Sensory branch

-   Passes through carpal tunnel

-   Sensory to 1st 3 & half fingers

-   Effected by carpal tunnel syndrome

-   May be injured during carpal tunnel release

 

 

 

 

 

References

 

Moores Clinically Oriented Anatomy

Pic (pathway): emedicine.medscape.com/article/1242387-overview